JTAG fuse vulnerability determination and protection using a trusted execution environment

ABSTRACT

A method of configuring a trusted security zone into a portable electronic device. The method comprises executing instructions on a processor of the portable electronic device that determine the state of a JTAG (JTAG) port of the portable electronic device, if the JTAG port is determined to be enabled, executing instructions on the processor preventing configuration of the trusted security zone into the portable electronic device, and if the JTAG port is determined to be disabled, configuring the trusted security zone into the portable electronic device, whereby a vulnerability to hacking the trusted security zone via an enabled JTAG port is reduced.

CROSS-REFERENCE TO RELATED APPLICATIONS

None.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

BACKGROUND

Network capable electronic devices are becoming increasingly prevalentin our daily lives. Additionally, more and more electronic devices thatdid not have network capabilities are getting network capable. With therapid development and popularization of network capable electronicdevices, a wide variety of increasingly sophisticated techniques arebeing deployed by attackers to take control of electronic devices andobtain confidential information, for example personal and payment data.The development of online application stores also helps cause rapiddevelopment, distribution and proliferation of malware applicationsacross the network. The behavior of uncontrollable electronic device orleak of confidential user information and their impact on the userexperience may have implications for user satisfaction with theelectronic device and/or the network service provider.

SUMMARY

In an embodiment, a method of configuring a trusted security zone into aportable electronic device is disclosed. The method comprises executinginstructions on a processor of the portable electronic device thatdetermine the state of a JTAG (JTAG) port of the portable electronicdevice, if the JTAG port is determined to be enabled, executinginstructions on the processor preventing configuration of the trustedsecurity zone into the portable electronic device, and if the JTAG portis determined to be disabled, configuring the trusted security zone intothe portable electronic device, wherein the trusted security zoneprovides hardware assisted trust, whereby a vulnerability to hacking thetrusted security zone via an enabled JTAG port is reduced.

In an embodiment, a method of protecting an electronic device from ahacking attack that exploits a JTAG (JTAG) port of the electronic devicethat has not been disabled is disclosed. The method comprises executinginstructions on a processor of the electronic device that determine thestate of a JTAG port of the electronic device, if the JTAG port isdetermined to be enabled, executing instructions on the processor of theelectronic device to detect a physical connection to the JTAG port, if aphysical connection to the JTAG port is detected, executing instructionson the processor preventing execution of trusted applications, and ifthe JTAG port is determined to be enabled, executing instructions on theprocessor preventing execution of software that reads from the JTAGport, whereby a vulnerability of the electronic device to a hackingattack that exploits an enabled JTAG port is reduced.

In an embodiment, a method of thwarting a hacking attack on a mobilephone via an enabled JTAG (JTAG) port of the mobile phone is disclosed.The method comprises executing instructions on a processor of the mobilephone that detect the state of the JTAG port as one of enabled ordisabled and when the JTAG port is determined to be enabled, taking afirst action to reduce vulnerability to hacking attacks via the enabledJTAG port.

These and other features will be more clearly understood from thefollowing detailed description taken in conjunction with theaccompanying drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure, referenceis now made to the following brief description, taken in connection withthe accompanying drawings and detailed description, wherein likereference numerals represent like parts.

FIG. 1 is an illustration of a communication system according to anembodiment of the disclosure.

FIG. 2 is a flow chart illustrating a method according to an embodimentof the disclosure.

FIG. 3 is a flow chart illustrating another method according to anembodiment of the disclosure.

FIG. 4 is an illustration of a mobile communication device according toan embodiment of the disclosure.

FIG. 5 is a block diagram of a mobile communication device according toan embodiment of the disclosure.

FIG. 6A is a block diagram of a software architecture of a mobilecommunication device according to an embodiment of the disclosure.

FIG. 6B is a block diagram of another software architecture of a mobilecommunication device according to an embodiment of the disclosure.

FIG. 7 is a block diagram of a computer system according to anembodiment of the disclosure.

DETAILED DESCRIPTION

It should be understood at the outset that although illustrativeimplementations of one or more embodiments are illustrated below, thedisclosed systems and methods may be implemented using any number oftechniques, whether currently known or not yet in existence. Thedisclosure should in no way be limited to the illustrativeimplementations, drawings, and techniques illustrated below, but may bemodified within the scope of the appended claims along with their fullscope of equivalents.

Problems may be caused by electronic devices that interfere with theproper operation of electronic devices or the coupled networks—forexample the ability of electronic devices to transmit or receiveconfidential information. The problems may result from malware thatinfected the electronic devices through the coupled network. Forexample, malware that infect an electronic device via Internet may tryto control the electronic device or steal personal or paymentinformation from the electronic device. “Backdoor” malware that infectedan electronic device may give attackers full access via joint testaction group (JTAG) ports to users' devices. Because devicemanufacturers may leave JTAG ports enabled intentionally oraccidentally, there is little the service provider or user can do toassure the reliability of the electronic devices with enabled JTAGports. The present disclosure teaches a method for proactively examiningthe status of a JTAG port of an electronic device and taking furtheraction to assure the reliability of the electronic device underdifferent circumstances.

For example, instructions may be executed by the processor of anelectronic device to determine the status of a JTAG port of theelectronic device and take corresponding proactive action. When the JTAGport is determined to be disabled, a trusted security zone is alsoconfigured into the electronic device. A JTAG port inspected certificateis also generated for the electronic device with the disabled JTAG port.Furthermore, the JTAG port inspected certificate is stored into securememory in the trusted security zone of the electronic device. When theJTAG port is determined to be enabled, a trusted security zone isprevented from configuring into the electronic device. Software thatreads from the JTAG port is prevented from executing on the electronicdevice with an enabled JTAG port. If a physical connection is detectedto the JTAG port after the JTAG port is determined to be enabled,execution of trusted applications on the electronic device will beprevented. In an embodiment, one or more untrusted applications may beprevented from executing on the electronic device after the JTAG port isdetermined to be enabled.

A trusted security zone provides chipsets with a hardware root of trust,a secure execution environment for applications, and secure access toperipherals. A hardware root of trust means the chipset should onlyexecute programs intended by the device manufacturer or vendor andresists software and physical attacks, and therefore remains trusted toprovide the intended level of security. The chipset architecture isdesigned to promote a programmable environment that allows theconfidentiality and integrity of assets to be protected from specificattacks. Trusted security zone capabilities are becoming features inboth wireless and fixed hardware architecture designs. Providing thetrusted security zone in the main mobile device chipset and protectingthe hardware root of trust removes the need for separate secure hardwareto authenticate the device or user. To ensure the integrity of theapplications requiring trusted data, such as a mobile financial servicesapplication, the trusted security zone also provides the secureexecution environment where only trusted applications can operate, safefrom attacks. Security is further promoted by restricting access ofnon-trusted applications to peripherals, such as data inputs and dataoutputs, while a trusted application is running in the secure executionenvironment. In an embodiment, the trusted security zone may beconceptualized as hardware assisted security.

A complete trusted execution environment (TEE) may be implementedthrough the use of the trusted security zone hardware and softwarearchitecture. The trusted execution environment is an executionenvironment that is parallel to the execution environment of the mainmobile device operating system. The trusted execution environment and/orthe trusted security zone may provide a base layer of functionalityand/or utilities for use of applications that may execute in the trustedsecurity zone. For example, in an embodiment, trust tokens may begenerated by the base layer of functionality and/or utilities of thetrusted execution environment and/or trusted security zone for use intrusted end-to-end communication links to document a continuity of trustof the communications. Through standardization of applicationprogramming interfaces (APIs), the trusted execution environment becomesa place to which scalable deployment of secure services can be targeted.A device which has a chipset that has a trusted execution environment onit may exist in a trusted services environment, where devices in thetrusted services environment are trusted and protected against attacks.The trusted execution environment can be implemented on mobile phonesand tablets as well as extending to other trusted devices such aspersonal computers, servers, sensors, medical devices, point-of-saleterminals, industrial automation, handheld terminals, automotive, etc.

The trusted security zone is implemented by partitioning all of thehardware and software resources of the mobile device into twopartitions: a secure partition and a normal partition. The securepartition may be implemented by a first physical processor, and thenormal partition may be implemented by a second physical processor.Alternatively, the secure partition may be implemented by a firstvirtual processor, and the normal partition may be implemented by asecond virtual processor. Placing sensitive resources in the securepartition can protect against possible attacks on those resources. Forexample, resources such as trusted software applications may run in thesecure partition and have access to hardware peripherals such as atouchscreen or a secure location in memory. Less secure peripherals suchas wireless radios may be disabled completely while the secure partitionis being accessed, while other peripherals may only be accessed from thesecure partition. While the secure partition is being accessed throughthe trusted execution environment, the main mobile operating system inthe normal partition is suspended, and applications in the normalpartition are prevented from accessing the secure peripherals and data.This prevents corrupted applications or malware applications frombreaking the trust of the device.

The trusted security zone is implemented by partitioning the hardwareand software resources to exist in a secure subsystem which is notaccessible to components outside the secure subsystem. The trustedsecurity zone is built into the processor architecture at the time ofmanufacture through hardware logic present in the trusted security zonewhich enables a perimeter boundary between the secure partition and thenormal partition. The trusted security zone may only be manipulated bythose with the proper credential and, in an embodiment, may not be addedto the chip after it is manufactured. Software architecture to supportthe secure partition may be provided through a dedicated secure kernelrunning trusted applications. Trusted applications are independentsecure applications which can be accessed by normal applications throughan application programming interface in the Trusted ExecutionEnvironment on a chipset that utilizes the trusted security zone.

In an embodiment, the normal partition applications run on a firstvirtual processor, and the secure partition applications run on a secondvirtual processor. Both virtual processors may run on a single physicalprocessor, executing in a time-sliced fashion, removing the need for adedicated physical security processor. Time-sliced execution comprisesswitching contexts between the two virtual processors to share processorresources based on tightly controlled mechanisms such as secure softwareinstructions or hardware exceptions. The context of the currentlyrunning virtual processor is saved, the context of the virtual processorbeing switched to is restored, and processing is restarted in therestored virtual processor. Time-sliced execution protects the trustedsecurity zone by stopping the execution of the normal partition whilethe secure partition is executing.

The two virtual processors context switch via a processor mode calledmonitor mode when changing the currently running virtual processor. Themechanisms by which the processor can enter monitor mode from the normalpartition are tightly controlled. The entry to monitor mode can betriggered by software executing a dedicated instruction, the SecureMonitor Call (SMC) instruction, or by a subset of the hardware exceptionmechanisms such as hardware interrupts, which can be configured to causethe processor to switch into monitor mode. The software that executeswithin monitor mode then saves the context of the running virtualprocessor and switches to the secure virtual processor.

The trusted security zone runs a separate operating system that is notaccessible to the device users. For security purposes, the trustedsecurity zone is not open to users for installing applications, whichmeans users do not have access to install applications in the trustedsecurity zone. This prevents corrupted applications or malwareapplications from executing powerful instructions reserved to thetrusted security zone and thus preserves the trust of the device. Thesecurity of the system is achieved at least in part by partitioning thehardware and software resources of the mobile phone so they exist in oneof two partitions, the secure partition for the security subsystem andthe normal partition for everything else. Placing the trusted securityzone in the secure partition and restricting access from the normalpartition protects against software and basic hardware attacks. Hardwarelogic ensures that no secure partition resources can be accessed by thenormal partition components or applications. A dedicated securepartition operating system runs in a virtual processor separate from thenormal partition operating system that likewise executes in its ownvirtual processor. Users may install applications on the mobile devicewhich may execute in the normal partition operating system describedabove. The trusted security zone runs a separate operating system forthe secure partition that is installed by the mobile device manufactureror vendor, and users are not able to install new applications in oralter the contents of the trusted security zone.

Turning now to FIG. 1, a communication system 100 is described. In anembodiment, the system 100 comprises a plurality of electronic devices102. The electronic device 102 may comprise one or more processors 104,one or more JTAG (JTAG) ports 106, an operating system 108, and a memory126. In an embodiment, the device 102 may have access to a network 118.A server computer 114 is coupled to the network 118, for example aserver 114 operated by a network service provider. The network 118 mayalso be accessible to an attacker computer 116. The network 118 maycomprise any combination of private and public networks.

It is understood that the system 100 may comprise any number of servers114 and any number of attackers 116. The electronic device 102 andattacker 116 may be any of a computer, a tablet computer, a mobilephone, a personal digital assistant (PDA), a media player, a gameconsole, an Internet digital media streaming device, or anothernetwork/communications capable device. Computers are discussed in moredetail hereinafter. The electronic device 102 and the attacker 116 mayaccess the network 118 through wired or wireless access network. Thewired access network may be abstracted in different ways and maycomprise cable modems and Ethernet routers, switches, or hubs. Thewireless access network may also be abstracted in different ways and maycomprise wireless access points, cable modems, Ethernet or wirelessrouters, switches, or hubs, servers and data storages such as homelocation registers (HLRs) or servers that implement the functionality ofhome location registers, visitor location registers (VLRs) or serversthat implement the functionality of visitor location registers, basetransceiver stations, base station controllers (BSCs), mobile switchingcenters (MSCs), and other network nodes that are specifically associatedwith providing wireless access and connectivity to the electronicdevices.

Non-trusted applications 112 are normal applications in the electronicdevice 102. When trusted applications 120 are executed in the trustedsecurity zone 124 of the electronic device 102, peripherals and data ofthe electronic device 102 may not be accessible to the non-trustedapplications 112. The non-trusted applications 112 are stored in apermissive sector 110 in the memory 126. The permissive sector 110 ofthe memory 126 is the normal partition in the memory 126. Normalapplications, the non-trusted applications 112, may be stored in thepermissive sector 110 in the memory 126. Additionally, non-secureresources may be stored in the permissive sector 110 in the memory 126.

Trusted applications 120 are authorized secure applications that maystore, transmit, or receive confidential data. The trusted applications120 may execute using higher level of security than the non-trustedapplications 112 that are executed in the operating system 108. Forexample, the trusted applications 120 may be applications used toperform payments, online banking, and enterprise authentication. Thetrusted applications 120 may also be applications that entail contentprotection such as email and corporate VPN. The trusted applications 120may be applications that handle confidential health records or personalhealth metrics. Additionally, the trusted applications 120 may beentertainment content streaming services that entail content protectionof the data in the form of music and video as well as authentication ofthe device 102 or the user, or another application that stores,transmits or receives confidential data. The trusted applications 120may be stored at least in part in the secure partition of the memory126, the trusted security zone 124. The trusted applications 120 may bebuilt in by device makers, original equipment manufacturer (OEM), orinstalled as users demand them. The trusted applications 120 canoriginate from different application providers. The trusted applications120 running in a trusted execution environment may have access to thefull power of a device's main processor and memory when the trustedapplications 120 are executed with hardware isolation that protects thetrusted applications 120 from user installed applications in the mainoperating system. Software and cryptographic isolation inside thetrusted execution environment protect the trusted applications 120 fromeach other. Hence, an unauthorized trusted application 120 may not havethe access to the security resources of another trusted application 120.

In an embodiment, the trusted security zone 124 is more than just asegment of memory. The trusted security zone 124 may also have adimension of processing. The trusted security zone 124 may provide thesecure execution environment for trusted applications 120 where onlytrusted applications 120 may operate, safe from attacks. The trustedsecurity zone 124 may be implemented by partitioning both hardware andsoftware resources of the electronic device 102 into two partitions: asecure partition and a normal partition. The secure partition may beimplemented by a distinct, separate, or dedicated physical processor,usually the first processor, from the processor by which the normalpartition may be implemented, usually the second processor.Alternatively, the secure partition may be implemented by a distinct,separate, or dedicated virtual processor from the virtual processor bywhich the normal partition may be implemented.

JTAG ports 106 may be used for software debugging for an embeddedsystem, firmware storing/updating for an embedded system, boundary scantesting for printed circuit boards, or other relevant purposes at themanufacturer of a device. When a JTAG port is not disabled aftermanufacturing, the fundamental cycle/chip level processing state of adevice may still be accessed. For example, with a single Chinesecharacter as a password, the fundamental cycle/chip level processingstate of a device may be accessed. Additionally, the device may bereprogrammed at the chip level via the JTAG port. Hence, the enabledJTAG port may be utilized as backdoor access that can give attackersfull access to a device to harm a device, collect confidential data fromthe device, or for another unauthorized use. The JTAG ports 106 may bedisabled at the manufacturer when the manufacturing and testing processis finished to prevent them from being utilized by attackers forunauthorized uses. However, the device vender/original equipmentmanufacturer may leave the JTAG ports 106 enabled by oversight ordeliberately. If the device vender/original equipment manufacturer failsto disable a JTAG port 106, there may still be physical, digital, orlogical connection to the JTAG port 106 and the JTAG port 106 is stillalive. The test port, test wire, test connection, or test voltage of theJTAG port 106 may still be utilized to go to the base of theprocessor/chip.

In an embodiment, the trusted security zone 124 functions as a testmonitor and decides whether an electronic device 102 may be trusted.Usually, actual pins are applied to check poles, functionality, orvoltages of the JTAG ports 106 to determine whether the JTAG ports 106are disabled. However, applying actual pins to test the voltages of theJTAG ports 106 after the chip is assembled/integrated into a circuitboard/an electronic device and shipped to the service provider may notbe feasible and the process may be emulated with an application in thetrusted execution environment or the trusted security zone installerprogram 128 that tries to enable trust. The trusted security zoneinstaller 128 may go to the right channels/ports/pins of the hardware tocheck the voltage of the JTAG port 106, channel, or pin, for examplewhether the voltage is zero or one. For example, when the JTAG fuse isenabled, the input impedance of the corresponding channel/port/pin maybe lowered, which may affect the voltage reference measurement.

For example, the application in the trusted execution environment or thetrusted security zone installer 128 may examine the status of the JTAGports 106 and take action to reduce the risk that the electronic device102 may be attacked by unauthorized parties. In an embodiment, when theJTAG ports 106 are determined to be disabled, the trusted security zoneinstaller 128 configures the trusted security zone into the electronicdevice 102. When the JTAG ports 106 are determined to be disabled, thetrusted security zone installer 128 may also generate a JTAG portinspected certificate 122 for the electronic device 102. Note that theexistence of the JTAG port inspected certificate 122 indicates orimplies a specific sequence of actions: the JTAG port 106 was checkedand determined to be disabled first; after the JTAG port 106 was checkedand found to be disabled, then the trusted security zone 124 wasinstalled second; and only after the trusted security zone 124 wasinstalled was the JTAG port inspected certificate 122 built.

When the JTAG ports 106 are determined to be enabled, the trustedsecurity zone installer 128 may send a message to a server computeridentifying the electronic device 102 as one with the enabled JTAG ports106. When the JTAG ports 106 are determined to be enabled, the trustedsecurity zone installer 128 may prevent configuration of the trustedsecurity zone 124 into the electronic device 102. The trusted securityzone installer 128 may also prevent trusted applications 120 fromexecuting or other applications that attempts to access resources of ahigher security level.

At the time of verifying and building up trust before installing thetrusted security zone, for example at the service provider side, thetrusted security zone installer 128 may be executed behind the trustedexecution environment by the processor 104 to test the status of theJTAG (JTAG) ports 106. For example, the determination of the status ofthe JTAG (JTAG) ports 106 is helpful before installation of softwarethat requires higher security level than non-trusted applications 112 inthe main operating system 108. In an embodiment, it is determinedwhether the JTAG port 106 is disabled or enabled after testing thestatus of the JTAG port 106. The JTAG ports 106 may be tested by testingwhether the fuses of JTAG ports 106 are blown. The determination of thestate of the JTAG ports 106 may be carried by reading from the JTAG port106 addresses.

If the JTAG port 106 on the electronic device 102 is determined to bedisabled, the trusted security zone installer 128 may take certainfurther action. For example, a trusted security zone 124 may beconfigured into the electronic device 102. In an embodiment, the trustedsecurity zone 124 provides hardware assisted trust/security.Additionally, a JTAG port inspected certificate 122 may be generated forthe device 102. The trusted execution environment may beincluded/integrated within an application processor 104 on theelectronic device 102. In an embodiment, the execution environmentcomprises the trusted security zone 124. In an embodiment, the trustedsecurity zone 124 may be configured or not be configured at all at theservice provider after the electronic device 102 is shipped from thedevice maker/assembler. When the trusted security zone 124 is configuredafter the JTAG ports 106 are determined to be disabled, the trustedsecurity zone 124 may be installed in a secure portion of the memory 126in the electronic device 102. The JTAG port inspected certificate 122 orexistence of the trusted security zone 124 may be taken as an indicatorfor the fact that the device 102 is stable, reliable, or trustworthy,for example by potential trusted applications 120. The JTAG portinspected certificate 122 may be stored into a trusted memory area ofthe trusted security zone 124. Additionally/alternatively, a parametervalue may be stored abstractly indicating that the JTAG port 106 isdisabled. The parameter may be stored in a trusted memory area of thesecure partition of the memory 126, the trusted security zone 124.

On the other hand, if the JTAG port 106 is determined to be enabled, thetrusted security zone installer 128 executed on the processor 104 maytake precautionary or remediating action. A message may be sent to theserver computer 114 identifying the electronic device 102 and indicatingthat the JTAG ports 106 of the electronic device 102 were determined tobe enabled. The message sent to the server computer 114 may be anelectronic message via the network 118. Downloading of confidentialinformation to the electronic device 102 may be prevented byinstructions executed on the processor 104 of the electronic device 102.For example, downloading of a credit card number or a credit cardpayment application may be prevented. Additionally, downloading offinancial applications to the electronic device 102 may be prevented.

Traditionally, JTAG fuses need to be blown to be disabled and soattackers or others would not have access to the memory 126 via the JTAGports 106 or to the very fundamental core of the processor 104 via theJTAG ports 106. In an embodiment, the trusted security zone installer128 may provide hardware assisted trust/security without blowing theJTAG fuses. For example, the trusted security zone installer 128 may beexecuted on the processor 104 to stop initializing trusted security zone124 configuration and prevent any future action that tries to start thetrusted security zone 124 configuration again. The trusted security zoneinstaller 128 may be executed on the processor 104 preventingconfiguration of the trusted security zone 124 into the electronicdevice 102 if the initialization of the trusted security zone 124 hasnot begun.

A hardware portion of the electronic device 102 intended forinstallation of a trusted security zone 124 may be marked as invalid oruntrusted. For example, the hardware portion of the electronic device102 intended for installation of a trusted security zone 124 may not beused for any purpose or only for non-trusted applications 112 orinformation that does not entail higher security level. Additionally,instructions may be executed on the processor 104 preventing executionof software that reads from the JTAG port 106. For example, throughoutthe lifetime of the electronic device 102, the trusted security zoneinstaller 128 may monitor and/or discipline the executables/programsthat are loaded on the JTAG ports 106 and may inhibit, pause, and/orshut down the executables/programs that read from the JTAG ports 106.

The trusted security zone installer 128 may also detect when a programis trying to modify any JTAG port 106 in an over-the-air fashion and mayinhibit, pause, and/or shut down the corresponding program. In anembodiment, an untrusted logo may be displayed on a display of theelectronic device 102 when the JTAG port 106 is determined to beenabled. For example, an untrusted logo may be displayed when theelectronic device 102 is turned on.

The trusted security zone installer 128 may be executed on the processor104 to detect a physical connection to the JTAG port 106. If a physicalconnection to the JTAG port 106 is detected, the trusted security zoneinstaller 128 may be executed on the processor 104 preventing executionof trusted applications 120.

Turning now to FIG. 2, a method 200 is described. At block 202,instructions are executed on a processor 104 of the portable electronicdevice 102 that determines the state of a JTAG port 106 of the portableelectronic device 102. For example, instructions are executed on theprocessor 104 to determine whether the JTAG port 106 is disabled. Forexample, the determination process of the status of the JTAG port 106may comprise the determination of whether the fuses of the JTAG ports106 are blown. The determination process of the status of the JTAG port106 may further comprise reading from the JTAG port 106 addresses.

If the JTAG port is not disabled, the method 200 proceeds to block 212.If the JTAG port is disabled, the method 200 proceeds to block 206. Atblock 212, instructions are executed on the processor 104 preventingconfiguration of the trusted security zone 124 into the portableelectronic device 102. When the JTAG port 106 is enabled, the electronicdevice is considered as unstable, unreliable, or untrustworthy, and sothe trusted security zone may not be configured into the electronicdevice 102. At block 206, the trusted security zone 124 is configuredinto the portable electronic device 102, wherein the trusted securityzone 124 provides hardware assisted trust or root of trust. At block208, after the trusted security zone is configured into the portableelectronic device, instructions are executed on the processor 104creating a JTAG port inspected certificate 122. The existence of theJTAG port inspected certificate 122 indicates or implies that the JTAGport 106 was checked, determined to be disabled, and the trustedsecurity zone 124 was installed. With the JTAG port inspectedcertificate 122, the electronic device 102 may be taken as stable,reliable, or trustworthy, for example by potential trusted applications120. With the JTAG port inspected certificate 122, the electronic device102 may be taken as stable, reliable, or trustworthy by confidentialinformation that requires higher security level than normal informationprocessed in the operating system 108 or stored in the permissive sectorof the memory 126. Additionally, the JTAG inspected certificate 122 maybe stored—off device—for future use in demonstrating integrity of devicetrust—as when a claim for unauthorized disclosure of confidentialinformation or hacking the device 102 is advanced. At block 210, theJTAG port inspected certificate 122 is stored into a trusted memory areaof the trusted security zone 124. The JTAG port inspected certificate122 may not be accessible with unauthorized attempts by the non-trustedapplications 112, which may assure the JTAG port inspected certificate122 as a trustworthy indicator for the credibility of the electronicdevice.

Turning now to FIG. 3, a method 300 is described. At block 302,instructions are executed on a processor 104 of the electronic device102 that determine the state of a JTAG port 106 of the electronic device102. At block 304, it is determined whether the JTAG port 106 isenabled. If the result of block 304 is false, which means the JTAG port106 is disabled, end the program. If the result of block 304 is true,which means the JTAG port 106 is enabled, block 306 is executed andinstructions are executed on the processor 104 preventing execution ofsoftware that reads from the JTAG port 106. When the JTAG port 106 isenabled, the electronic device 102 is considered to be unreliable andthe electronic device 102 may be vulnerable to attackers 116 via theJTAG port 106. The JTAG port 106 may be exploited by attackers to accessthe memory 126 and reprogram the electronic device 102. Thus block 306is helpful when the JTAG port 106 has been left enabled. At block 308,instructions are executed on the processor 104 of the electronic device102 to detect a physical connection to the JTAG port 106. The possibleways that the JTAG port 106 is enabled comprise digital, physical, orlogical connection to the JTAG port 106. Here instructions are executedto detect specifically physical connection. At block 310, it isdetermined whether a physical connection to the JTAG port 106 isdetected. If the result of block 310 is false, which means no physicalconnection to the JTAG port 106 is detected, end the program. If theresult of block 310 is true, which means a physical connection to theJTAG port 106 is detected, block 312 is executed. At block 312,instructions are executed on the processor 104 preventing execution oftrusted applications 120. Trusted applications 120 entail highersecurity level, but the electronic device 102 may not be reliable whenthe JTAG port 106 is enabled. Hence, the trusted applications may not beallowed to be executed on the electronic device 102.

FIG. 4 depicts the mobile device 400, which is operable for implementingaspects of the present disclosure, but the present disclosure should notbe limited to these implementations. Though illustrated as a mobilephone, the mobile device 400 may take various forms including a wirelesshandset, a pager, a personal digital assistant (PDA), a gaming device,or a media player. The mobile device 400 includes a display 402 and atouch-sensitive surface and/or keys 404 for input by a user. The mobiledevice 400 may present options for the user to select, controls for theuser to actuate, and/or cursors or other indicators for the user todirect. The mobile device 400 may further accept data entry from theuser, including numbers to dial or various parameter values forconfiguring the operation of the handset. The mobile device 400 mayfurther execute one or more software or firmware applications inresponse to user commands. These applications may configure the mobiledevice 400 to perform various customized functions in response to userinteraction. Additionally, the mobile device 400 may be programmedand/or configured over-the-air, for example from a wireless basestation, a wireless access point, or a peer mobile device 400. Themobile device 400 may execute a web browser application which enablesthe display 402 to show a web page. The web page may be obtained viawireless communications with a base transceiver station, a wirelessnetwork access node, a peer mobile device 400 or any other wirelesscommunication network or system.

FIG. 5 shows a block diagram of the mobile device 400. While a varietyof known components of handsets are depicted, in an embodiment a subsetof the listed components and/or additional components not listed may beincluded in the mobile device 400. The mobile device 400 includes adigital signal processor (DSP) 502 and a memory 504. As shown, themobile device 400 may further include an antenna and front end unit 506,a radio frequency (RF) transceiver 508, a baseband processing unit 510,a microphone 512, an earpiece speaker 514, a headset port 516, aninput/output interface 518, a removable memory card 520, a universalserial bus (USB) port 522, an infrared port 524, a vibrator 526, akeypad 528, a touch screen liquid crystal display (LCD) with a touchsensitive surface 530, a touch screen/LCD controller 532, a camera 534,a camera controller 536, and a global positioning system (GPS) receiver538. In an embodiment, the mobile device 400 may include another kind ofdisplay that does not provide a touch sensitive screen. In anembodiment, the DSP 502 may communicate directly with the memory 504without passing through the input/output interface 518. Additionally, inan embodiment, the mobile device 400 may comprise other peripheraldevices that provide other functionality.

The DSP 502 or some other form of controller or central processing unitoperates to control the various components of the mobile device 400 inaccordance with embedded software or firmware stored in memory 504 orstored in memory contained within the DSP 502 itself. In addition to theembedded software or firmware, the DSP 502 may execute otherapplications stored in the memory 504 or made available via informationcarrier media such as portable data storage media like the removablememory card 520 or via wired or wireless network communications. Theapplication software may comprise a compiled set of machine-readableinstructions that configure the DSP 502 to provide the desiredfunctionality, or the application software may be high-level softwareinstructions to be processed by an interpreter or compiler to indirectlyconfigure the DSP 502.

The DSP 502 may communicate with a wireless network via the analogbaseband processing unit 510. In some embodiments, the communication mayprovide Internet connectivity, enabling a user to gain access to contenton the Internet and to send and receive e-mail or text messages. Theinput/output interface 518 interconnects the DSP 502 and variousmemories and interfaces. The memory 504 and the removable memory card520 may provide software and data to configure the operation of the DSP502. Among the interfaces may be the USB port 522 and the infrared port524. The USB port 522 may enable the mobile device 400 to function as aperipheral device to exchange information with a personal computer orother computer system. The infrared port 524 and other optional portssuch as a Bluetooth® interface or an IEEE 802.11 compliant wirelessinterface may enable the mobile device 400 to communicate wirelesslywith other nearby handsets and/or wireless base stations.

The keypad 528 couples to the DSP 502 via the interface 518 to provideone mechanism for the user to make selections, enter information, andotherwise provide input to the mobile device 400. Another inputmechanism may be the touch screen LCD 530, which may also display textand/or graphics to the user. The touch screen LCD controller 532 couplesthe DSP 502 to the touch screen LCD 530. The GPS receiver 538 is coupledto the DSP 502 to decode global positioning system signals, therebyenabling the mobile device 400 to determine its position.

FIG. 6A illustrates a software environment 602 that may be implementedby the DSP 502. The DSP 502 executes operating system software 604 thatprovides a platform from which the rest of the software operates. Theoperating system software 604 may provide a variety of drivers for thehandset hardware with standardized interfaces that are accessible toapplication software. The operating system software 604 may be coupledto and interact with application management services (AMS) 606 thattransfer control between applications running on the mobile device 400.Also shown in FIG. 6A are a web browser application 608, a media playerapplication 610, and JAVA applets 612. The web browser application 608may be executed by the mobile device 400 to browse content and/or theInternet, for example when the mobile device 400 is coupled to a networkvia a wireless link. The web browser application 608 may permit a userto enter information into forms and select links to retrieve and viewweb pages. The media player application 610 may be executed by themobile device 400 to play audio or audiovisual media. The JAVA applets612 may be executed by the mobile device 400 to provide a variety offunctionality including games, utilities, and other functionality.

FIG. 6B illustrates an alternative software environment 620 that may beimplemented by the DSP 502. The DSP 502 executes operating systemsoftware 628 (for example an operating system kernel) and an executionruntime 630. The DSP 502 executes applications 622 that may execute inthe execution runtime 630 and may rely upon services provided by theapplication framework 624. Applications 622 and the applicationframework 624 may rely upon functionality provided via the libraries626.

FIG. 7 illustrates a computer system 380 suitable for implementing oneor more embodiments disclosed herein. The computer system 380 includes aprocessor 382 (which may be referred to as a central processor unit orCPU) that is in communication with memory devices including secondarystorage 384, read only memory (ROM) 386, random access memory (RAM) 388,input/output (I/O) devices 390, and network connectivity devices 392.The processor 382 may be implemented as one or more CPU chips.

It is understood that by programming and/or loading executableinstructions onto the computer system 380, at least one of the CPU 382,the RAM 388, and the ROM 386 are changed, transforming the computersystem 380 in part into a particular machine or apparatus having thenovel functionality taught by the present disclosure. It is fundamentalto the electrical engineering and software engineering arts thatfunctionality that can be implemented by loading executable softwareinto a computer can be converted to a hardware implementation by wellknown design rules. Decisions between implementing a concept in softwareversus hardware typically hinge on considerations of stability of thedesign and numbers of units to be produced rather than any issuesinvolved in translating from the software domain to the hardware domain.Generally, a design that is still subject to frequent change may bepreferred to be implemented in software, because re-spinning a hardwareimplementation is more expensive than re-spinning a software design.Generally, a design that is stable that will be produced in large volumemay be preferred to be implemented in hardware, for example in anapplication specific integrated circuit (ASIC), because for largeproduction runs the hardware implementation may be less expensive thanthe software implementation. Often a design may be developed and testedin a software form and later transformed, by well known design rules, toan equivalent hardware implementation in an application specificintegrated circuit that hardwires the instructions of the software. Inthe same manner as a machine controlled by a new ASIC is a particularmachine or apparatus, likewise a computer that has been programmedand/or loaded with executable instructions may be viewed as a particularmachine or apparatus.

The secondary storage 384 is typically comprised of one or more diskdrives or tape drives and is used for non-volatile storage of data andas an over-flow data storage device if RAM 388 is not large enough tohold all working data. Secondary storage 384 may be used to storeprograms which are loaded into RAM 388 when such programs are selectedfor execution. The ROM 386 is used to store instructions and perhapsdata which are read during program execution. ROM 386 is a non-volatilememory device which typically has a small memory capacity relative tothe larger memory capacity of secondary storage 384. The RAM 388 is usedto store volatile data and perhaps to store instructions. Access to bothROM 386 and RAM 388 is typically faster than to secondary storage 384.The secondary storage 384, the RAM 388, and/or the ROM 386 may bereferred to in some contexts as computer readable storage media and/ornon-transitory computer readable media.

I/O devices 390 may include printers, video monitors, liquid crystaldisplays (LCDs), touch screen displays, keyboards, keypads, switches,dials, mice, track balls, voice recognizers, card readers, paper tapereaders, or other well-known input devices.

The network connectivity devices 392 may take the form of modems, modembanks, Ethernet cards, universal serial bus (USB) interface cards,serial interfaces, token ring cards, fiber distributed data interface(FDDI) cards, wireless local area network (WLAN) cards, radiotransceiver cards such as code division multiple access (CDMA), globalsystem for mobile communications (GSM), long-term evolution (LTE),worldwide interoperability for microwave access (WiMAX), and/or otherair interface protocol radio transceiver cards, and other well-knownnetwork devices. These network connectivity devices 392 may enable theprocessor 382 to communicate with the Internet or one or more intranets.With such a network connection, it is contemplated that the processor382 might receive information from the network, or might outputinformation to the network in the course of performing theabove-described method steps. Such information, which is oftenrepresented as a sequence of instructions to be executed using processor382, may be received from and outputted to the network, for example, inthe form of a computer data signal embodied in a carrier wave.

Such information, which may include data or instructions to be executedusing processor 382 for example, may be received from and outputted tothe network, for example, in the form of a computer data baseband signalor signal embodied in a carrier wave. The baseband signal or signalembedded in the carrier wave, or other types of signals currently usedor hereafter developed, may be generated according to several methodswell known to one skilled in the art. The baseband signal and/or signalembedded in the carrier wave may be referred to in some contexts as atransitory signal.

The processor 382 executes instructions, codes, computer programs,scripts which it accesses from hard disk, floppy disk, optical disk(these various disk based systems may all be considered secondarystorage 384), ROM 386, RAM 388, or the network connectivity devices 392.While only one processor 382 is shown, multiple processors may bepresent. Thus, while instructions may be discussed as executed by aprocessor, the instructions may be executed simultaneously, serially, orotherwise executed by one or multiple processors. Instructions, codes,computer programs, scripts, and/or data that may be accessed from thesecondary storage 384, for example, hard drives, floppy disks, opticaldisks, and/or other device, the ROM 386, and/or the RAM 388 may bereferred to in some contexts as non-transitory instructions and/ornon-transitory information.

In an embodiment, the computer system 380 may comprise two or morecomputers in communication with each other that collaborate to perform atask. For example, but not by way of limitation, an application may bepartitioned in such a way as to permit concurrent and/or parallelprocessing of the instructions of the application. Alternatively, thedata processed by the application may be partitioned in such a way as topermit concurrent and/or parallel processing of different portions of adata set by the two or more computers. In an embodiment, virtualizationsoftware may be employed by the computer system 380 to provide thefunctionality of a number of servers that is not directly bound to thenumber of computers in the computer system 380. For example,virtualization software may provide twenty virtual servers on fourphysical computers. In an embodiment, the functionality disclosed abovemay be provided by executing the application and/or applications in acloud computing environment. Cloud computing may comprise providingcomputing services via a network connection using dynamically scalablecomputing resources. Cloud computing may be supported, at least in part,by virtualization software. A cloud computing environment may beestablished by an enterprise and/or may be hired on an as-needed basisfrom a third party provider. Some cloud computing environments maycomprise cloud computing resources owned and operated by the enterpriseas well as cloud computing resources hired and/or leased from a thirdparty provider.

In an embodiment, some or all of the functionality disclosed above maybe provided as a computer program product. The computer program productmay comprise one or more computer readable storage medium havingcomputer usable program code embodied therein to implement thefunctionality disclosed above. The computer program product may comprisedata structures, executable instructions, and other computer usableprogram code. The computer program product may be embodied in removablecomputer storage media and/or non-removable computer storage media. Theremovable computer readable storage medium may comprise, withoutlimitation, a paper tape, a magnetic tape, magnetic disk, an opticaldisk, a solid state memory chip, for example analog magnetic tape,compact disk read only memory (CD-ROM) disks, floppy disks, jump drives,digital cards, multimedia cards, and others. The computer programproduct may be suitable for loading, by the computer system 380, atleast portions of the contents of the computer program product to thesecondary storage 384, to the ROM 386, to the RAM 388, and/or to othernon-volatile memory and volatile memory of the computer system 380. Theprocessor 382 may process the executable instructions and/or datastructures in part by directly accessing the computer program product,for example by reading from a CD-ROM disk inserted into a disk driveperipheral of the computer system 380. Alternatively, the processor 382may process the executable instructions and/or data structures byremotely accessing the computer program product, for example bydownloading the executable instructions and/or data structures from aremote server through the network connectivity devices 392. The computerprogram product may comprise instructions that promote the loadingand/or copying of data, data structures, files, and/or executableinstructions to the secondary storage 384, to the ROM 386, to the RAM388, and/or to other non-volatile memory and volatile memory of thecomputer system 380.

In some contexts, the secondary storage 384, the ROM 386, and the RAM388 may be referred to as a non-transitory computer readable medium or acomputer readable storage media. A dynamic RAM embodiment of the RAM388, likewise, may be referred to as a non-transitory computer readablemedium in that while the dynamic RAM receives electrical power and isoperated in accordance with its design, for example during a period oftime during which the computer 380 is turned on and operational, thedynamic RAM stores information that is written to it. Similarly, theprocessor 382 may comprise an internal RAM, an internal ROM, a cachememory, and/or other internal non-transitory storage blocks, sections,or components that may be referred to in some contexts as non-transitorycomputer readable media or computer readable storage media.

While several embodiments have been provided in the present disclosure,it should be understood that the disclosed systems and methods may beembodied in many other specific forms without departing from the spiritor scope of the present disclosure. The present examples are to beconsidered as illustrative and not restrictive, and the intention is notto be limited to the details given herein. For example, the variouselements or components may be combined or integrated in another systemor certain features may be omitted or not implemented.

Also, techniques, systems, subsystems, and methods described andillustrated in the various embodiments as discrete or separate may becombined or integrated with other systems, modules, techniques, ormethods without departing from the scope of the present disclosure.Other items shown or discussed as directly coupled or communicating witheach other may be indirectly coupled or communicating through someinterface, device, or intermediate component, whether electrically,mechanically, or otherwise. Other examples of changes, substitutions,and alterations are ascertainable by one skilled in the art and could bemade without departing from the spirit and scope disclosed herein.

What is claimed is:
 1. A method of configuring a trusted security zoneinto a portable electronic device, comprising: executing instructions ona processor of the portable electronic device that determine the stateof a Joint Test Action Group (JTAG) port of the portable electronicdevice; responsive to a determination that the JTAG port is enabled,executing instructions on the processor preventing configuration of thetrusted security zone into the portable electronic device; responsive toa determination that the JTAG port is disabled, configuring the trustedsecurity zone into the portable electronic device, wherein the trustedsecurity zone provides hardware assisted trust, wherein configuring thetrusted security zone comprises installing the trusted security zone ina secure portion of a memory in the portable electronic device; andafter the trusted security zone is configured into the portableelectronic device, executing instructions on the processor creating aJTAG port inspected certificate and storing the JTAG port inspectedcertificate into a trusted memory area of the trusted security zone,wherein executing instructions on the processor preventing configurationof the trusted security zone into the portable electronic deviceresponsive to the determination that the JTAG port is enabled reduces avulnerability to hacking the trusted security zone via the enabled JTAGport.
 2. The method of claim 1, wherein determining the state of theJTAG port comprises determining whether the fuses of the JTAG port areblown.
 3. The method of claim 1, wherein determining the state of theJTAG port comprises reading from the JTAG port addresses.
 4. The methodof claim 1, further comprising, responsive to the determination that theJTAG port is enabled, sending an electronic message to a server computeridentifying the portable electronic device and indicating that the JTAGport of the device was determined to be enabled, whereby a purchaser ofportable electronic devices accumulates statistical information on theperformance of vendors based on the message.
 5. The method of claim 1,wherein the portable electronic device is one of a mobile phone, apersonal digital assistant (PDA), or a media player.
 6. The method ofclaim 1, wherein the portable electronic device is one of a laptopcomputer, a tablet computer, or a notebook computer.
 7. A method ofprotecting an electronic device from a hacking attack that exploits aJoint Test Action Group (JTAG) port of the electronic device that hasnot been disabled, comprising: executing instructions on a processor ofthe electronic device that determine the state of a JTAG port of theelectronic device; responsive to a determination that the JTAG port isenabled, executing instructions on the processor of the electronicdevice to detect a physical connection to the JTAG port; responsive todetecting a physical connection to the JTAG port, executing instructionson the processor preventing execution of trusted applications;responsive to a determination that the JTAG port is enabled, executinginstructions on the processor preventing execution of software thatreads from the JTAG port; and responsive to a determination that theJTAG port is enabled, preventing downloading of at least one ofconfidential information, financial applications, a credit card number,or a credit card payment application, wherein executing instructions onthe processor preventing execution of the trusted applicationsresponsive to detecting the physical connection to the JTAG port,executing instructions on the processor preventing execution of thesoftware that reads from the JTAG port responsive to the determinationthat the JTAG port is enabled, and preventing downloading of at leastone of confidential information, financial applications, a credit cardnumber, or a credit card payment application responsive to thedetermination that the JTAG port is enabled reduces a vulnerability ofthe electronic device to a hacking attack that exploits the enabledJTAG.
 8. The method of claim 7, wherein the electronic device is one ofa mobile phone, a laptop computer, a tablet computer, a notebookcomputer, a server computer, a router, or an embedded system.
 9. Themethod of claim 7, wherein determining the state of the JTAG portcomprises reading from addresses associated with the JTAG port.
 10. Themethod of claim 7, wherein determining the state of the JTAG portcomprises determining the state of JTAG fuses.
 11. The method of claim10, wherein responsive to a determination that the JTAG fuses areintact, storing a parameter value abstractly indicating that the JTAGport is enabled.
 12. The method of claim 10, wherein responsive to adetermination that the JTAG fuses are blown, storing a parameter valueabstractly indicating that the JTAG port is disabled.
 13. The method ofclaim 7, further comprising sending a message to a server computerindicating that the JTAG port is not disabled.
 14. A method of thwartinga hacking attack on a mobile phone via an enabled Joint Test ActionGroup (JTAG) port of the mobile phone, comprising: executinginstructions on a processor of the mobile phone that detect the state ofthe JTAG port as one of enabled or disabled; responsive to adetermination that the JTAG port is enabled, taking a first action toreduce vulnerability to hacking attacks via the enabled JTAG port,wherein the first action comprises preventing downloading of at leastone of confidential information, financial applications, a credit cardnumber, or a credit card payment application; responsive to adetermination that the JTAG port is disabled, configuring a trustedsecurity zone into the mobile phone, wherein configuring the trustedsecurity zone comprises installing the trusted security zone in a secureportion of a memory in the mobile phone; and after the trusted securityzone is configured into the mobile phone, executing instructions on theprocessor creating a JTAG port inspected certificate and storing theJTAG port inspected certificate into a trusted memory area of thetrusted security zone.
 15. The method of claim 14, further comprisingwhen the JTAG port is determined to be enabled, marking a hardwareportion of the mobile phone intended for installation of a trustedsecurity zone as one of invalid or untrusted.